This invention concerns fluid dispensing systems which are particularly, but not exclusively, suitable for incorporation in drinks vending machines.
The term "fluid" as used herein is intended to include liquids, such as water, perfume and other low viscosity liquids.
Fluid dispensing systems have been proposed heretofore. U.S. Pat. No. 1,327,768 discloses a tank for holding liquid through which a wheel arrangement is adapted to rotate, the arrangement having a hub disc mounted on a solid shaft, the disc supporting six conduits in equi-spaced relationship radially of the shaft. At the one end of each conduit remote from the disc a measuring container is mounted having a restricted entry. The conduits are similarly cranked and pass through the disc parallel to the axis of the shaft with fluid collected in the containers being sequentially discharged from the respective conduit into a chamber to be discharged therefrom through a discharge pipe.
FR-A-2 160 243 discloses a pair of tanks for liquid into each of which a wheel arrangement including a disc is adapted to rotate, the arrangements being unitary with the two discs connected through a hub and rotatable in a central mounting by a solid shaft secured to one of the discs. Each arrangement has three containers mounted on the respective disc and is rotated through the respective tank to sequentially collect liquid through two openings (25 and 9) in each container and discharge liquid collected through respective conduits into a single collection tank 16.
Drinks vending machines, whether free-standing or table-top supported, generally operate by dispensing water and powdered ingredients from separate sources to a mixing zone. The mixing zone may be separate from a drinks cup in which the drink will be supplied or may be the drinks cup itself. Either way it is important that a pre-selected amount of water is discharged to the mixing zone so that the drink produced is of the required strength and to avoid water spillage in or from the vending machine.
It is further desirable that the fluid dispensing system operate relatively simply in order to reduce the risk of breakdown.
Typically drinks vending machines and other fluid dispensers use solenoid valves for controlling flow of fluid but these valves are prone to becoming clogged and so, without warning, stick in one position.
An object of this invention is to provide a simple fluid dispensing system suitable for a drinks vending machine and other applications.
According to this invention, there is provided a fluid dispensing system comprising a tank for the fluid, and means for extracting a quantity of fluid from the tank and for directing the extracted fluid to one or more selected receptacles, the means comprising a fluid collecting device including a vessel and an outlet pipe in fluid communication, the vessel being for rotary passage through the tank and having a restricted entry aperture wherein the vessel and outlet pipe are connected through a rotatable tubular shaft which extends between opposed walls of the tank and is journalled for rotation therein with one of its ends closed off and the other projecting through the respective tank wall, the vessel being mounted on the shaft with the outlet pipe being connected to the projecting end of the shaft exteriorly of the tank to extend diametrically away from the vessel, rotary passage of the vessel causing rotary passage of the outlet pipe outside of the tank, whereby, in use with fluid in the tank, during a rotary cycle of the device air exhausts from the vessel through the outlet pipe as fluid ingresses into the vessel through the aperture during a filling operation, and air flows into the vessel through the aperture as fluid is dispensed through the outlet pipe in a dispensing operation.
Preferably, the fluid is raised from a supply thereof in the tank and discharged by gravity to the one or more selected receptacles.
Preferably also, the vessel is closed and the restricted entry aperture is a circular hole. The amount of fluid which ingresses into the vessel beneficially depends on the size of the hole and the dwell time during which the vessel is in the fluid in the tank. The volume of fluid retained in the vessel when moving from a filling position to a dispensing position desirably depends on the size of hole and the speed of rotation.
The tank is desirably of two part construction comprising an upper part to which a lower fluid-holding part is removably secured. The upper part is beneficially mounted on a support, for example a supporting part of a drinks vending machine.
In a preferred embodiment, the vessel is sectoral in side elevation, and is mounted at its vertex on the rotatable tubular shaft. The wall of the shaft within the vessel is perforate to admit fluid with a single or multiple openings. Further, the single opening is elongate, preferably along its length. The vessel has preferably two sectoral sides spaced apart by radial walls and an arcuate wall in which the opening is provided. The vessel being rotatable about the axis of the shaft preferably passes through the fluid from a park position where it is normally out of the fluid to one or more selected positions of a plurality of dispensing positions to discharge through the outlet pipe fluid collected during its rotation between said park and dispensing positions.
The shaft preferably extends through the upper part of the tank to be closed on the outside of the rear side thereof and to be connected on the outside of the front side of the tank to the outlet pipe, preferably at right angles to the shaft.
The shaft is preferably rotated by a motor, preferably an electrically operated motor that is program controlled. A position sensing device, for example a magnetic sensor, may be used to reference the position of the shaft during rotation. The shaft may have a toothed wheel thereon with a toothed belt drive employed to mesh with a toothed output gear of the motor to rotate the wheel. The motor may conveniently be mounted on the outside of a side of the tank.
The fluid dispensing system of the invention preferably has a plurality of upright elongate chambers for receiving fluid from the outlet. The chambers are preferably arranged in a manifold of individual chambers. Preferably, the tops of the chambers are arranged radially relative to the axis of rotation of the shaft. Desirably, the chambers each has an outlet for transferring any fluid received to a mixing zone where it is mixed with powdered and/or possibly other liquid ingredients to produce a mixture, i.e. a desired drink in the case of being incorporated in a drinks vending machine, or other desired mixture in other cases.
The motor is preferably programmed to rotate the vessel from its `park` position through a reference position and a filling position to one or more discharge positions according to the desired combination of chambers necessary for producing the selected mixed product.
The outlet pipe may have a volume control, such as by means of a restrictor screw say through a side of the outlet pipe, whereby the amount of air to be displaced in allowing fluid into the outlet may be controlled.